Cunning Nightbonder

Spells with flash that you control but didn't cast (perhaps because they're copies of a spell or because you took control of them from another player) can be countered.

A spell or ability that counters spells can still target spells with flash you cast. When that spell or ability resolves, your spell won't be countered, but any additional effects of the countering spell or ability will still happen.

To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions (such as that of Cunning Nightbonder). The mana value of the spell remains unchanged, no matter what the total cost to cast it was.